过期期刊排架的实践及认识——以广西师范学院图书馆为例

介绍了各种期刊排架法，对目前常用的排架方法进行了对比分析；同时也介绍了广西师范学院图书馆过刊的排架现状及笔者对该现状的一点看法。     

播种方式和行距对燕麦/饲用豌豆混播草地生产性能及种间关系的影响

为筛选出适宜于青藏高原高寒地区种植推广的播种方式及播种行距,本研究以燕麦（Avena sativa）和饲用豌豆（Pisum sativum）为试验材料,探求其在混播、间作及不同行距下的生产性能及种间竞争关系。结果表明：混播处理生产性能优于间作处理,30 cm处理优于其他行距。混播草地土地当量比均大于1,具有混播优势,混播草地中燕麦与饲用豌豆的种间相容性较好,两者间促进作用大于竞争作用,行距为30 cm与25 cm时,燕麦的竞争能力大于饲用豌豆。综合评价显示,青藏高原高寒地区燕麦/饲用豌豆混播行距30 cm时效果最佳,干草产量最高,适于建植应用。     

杨树固沙林密度、配置与林木生长过程的关系

在科尔沁沙地证明低覆盖度行带式固沙林具有显著的防风效果后,进一步对雨养条件下杨树(赤峰-36号)固沙林的密度、配置及林木生长过程与林龄的动态关系进行研究.结果表明: 1)1～5 a林木的生长基本不受密度的影响,密度大单位面积材积量大;6～11 a是密度对林木生长的显著影响阶段,杨树固沙林的胸径、株高和材积量的增长率随林龄增大而逐年加快;大约在11 a之后趋于稳定;单位活立木蓄积最大(153.39 m3·hm-2)的固沙林密度是825株·hm-2,其他密度按蓄积大小排序依次为540株·hm-2、420株·hm-2和1 215株·hm-2;2)边缘林木的平均胸径和单株材积量分别比林内高20%～70%和90%～260%,且低密度林分的边缘林木的生长优势比高密度林分边缘林木的生长优势更加明显;3)同密度(500株·hm-2)13 a的一行一带式固沙林,其胸径、树高和材积量分别比等株行距的片林高37.4%、17.4%和81%;而10 a的两行一带式的胸径、树高和材积量分别比等株行距的片林高19.8%、16.2%和64.8%,说明行带式配置还具有生物生产力优势.     

Optimum planting density for Japanese oak (Quercus mongolica var.grosseserrata) based on spacing experiment with systematic design

A spacing experiment for Japanese oak (Quercus mongolica var.grosseserrata) with Nelder's design have been studied at the Kyushu University Forest in Hokkaido, since 1975. The oak seedlings were planted according to systematic spacings which were 20 levels varying gradually from 40,816 to 1,086 seedlings per hectare with concentric circular arcs (22 in number) and spokes (41 in number). In 1992 when the planted oak seedlings were 18-year-old, DBH, crown diameter, total height and clear length of the survival trees were measured. Based on the results obtained from analyzing the relationships between planting density and the mean values of each block, the optimum planting density should be 7,241 seedlings per hectare. The title is tentative translation from the original Japanese title by the authors of this paper.     

木材材性株内径向变异模式初探──Ⅲ.种植密度对湿地松、火炬松木材密度径向变异模式的影响

对两个地区不同种植密度的湿地松、火炬松进行了微密度分析，研究了种植密度对木材密度径向变异模式的影响。主要结果是：种植密度对湿地松和火炬松各密度特征值径向变异模式的影响，主要表现在变异曲线平均水平高低的变动，而对变异曲线形状的影响并不显著。种植密度对湿地松和火炬松各年轮宽特征值径向变异模式的影响，主要表现在年轮宽度RW和早材宽度EW变异曲线平均水平高低的变动和RW、EW与晚材宽度LW变异曲线形状的变动。种植密度对年轮密度RD的影响从年轮内宽度和年轮密度变异曲线平均水平高低两个方面起作用，出现较复杂的情况，并非所有情况下都是单调的正相关。     

营养面积和行株距配置对红香芋植株光合特性及产量品质的影响

以地方品种‘建昌红香芋’为材料,设置6个植株配置组合,研究其对植株生长、冠层特征、光合参数及球茎产量品质等指标的影响,以探讨营养面积和行株距配置对芋植株光合特性及产量品质的影响。结果表明,单株营养面积越小,芋植株株高越高,叶片开展度越低。在营养面积为0.165m2和0.220m2的条件下,宽窄行为(70+40)cm的植株冠层光合有效辐射透过率显著高于宽窄行为(80+30)cm的植株,而光合有效辐射截获率则相反。株距为30cm的芋植株叶面积指数和冠层光合有效辐射截获率最大,冠层光合有效辐射透过率最小,植株的净光合速率(Pn)最低,其单株球茎产量最低,品质最差。株距为35cm时,芋植株具有较高的Pn,形成的单位面积球茎产量最高,品质最好。说明,合理的营养面积和行株距配置可有效调控芋植株冠层形态结构和光合有效辐射(PAR),影响光合作用,并最终影响球茎产量和品质。     

密度和行距配置对玉米产量及其构成因素的影响

试验以桂单162为供试材料,采用2因素裂区设计,密度为主处理,行距为副处理,研究4个种植密度下4种行距配置方式对玉米产量及其构成因素的影响。结果表明:密度、行距及密度与行距互作对玉米出籽率的影响不显著;密度、密度与行距互作对玉米结实长度影响达到极显著水平,随着密度加大结实长度越短,不同密度与不同行距配置才能对结实长度起到最大的影响作用;种植密度对穗粗影响达到显著水平,穗粗随着种植密度加大而变小;密度、行距及密度与行距互作对产量的影响达到极显著水平,4种种植行距下4 000株/667m2产量最高,4个密度下60 cm单行单株种植产量最高,桂单162以4 500株/667m2,60 cm单行单株种植产量最高。     

糜子品种不同行距和不同密度处理下对其产量及农艺性状的影响

以糜子生产上正常行距33cm,留苗密度7万株/667m2为对照,研究糜子在不同宽行距处理下,667m2保苗3万株的稀播密度,是否能提高其产量的繁殖系数,试图找出一种较好的宽行距处理,从而在糜子的实际生产应用中以取代常规的窄行距,高密度种植,并且在糜子生产中得以大面的推广.     

Size selectivity of the Spisula solida dredge in relation to tooth spacing and mesh size

A study was undertaken on the northwestern coast of Portugal to evaluate the selectivity effect of both tooth spacing and mesh size on the catch of the white clam (Spisula solida). Two typical clam dredges, equipped with different tooth spacing and mesh size, were towed side by side. Three tooth spacing (20, 40 and 60 mm) and three mesh sizes (35, 40 and 50 mm) were investigated. The dredge selectivity experiments were performed by attaching a cover bag with a 20 mm mesh to the gear. Individual hauls were analysed by the SELECT model. The Fryer’s mixed model of between-haul variation was also applied to data. The results showed that the space between teeth does not have an effect on selectivity. Tooth length was directly related to the dredge’s capture efficiency. The only factor that contributed to dredge size selection was mesh size. The 50% retention lengths estimated for mesh sizes 30, 40 and 50 mm were 25.68, 26.35 and 31.94 mm, respectively. For all mesh sizes, very narrow selection ranges were observed. The most appropriate mesh size to be enforced within the Portuguese northwestern S. solida fishery should be 40 mm.